Sign up to receive free email alerts when patent applications with chosen keywords are publishedSIGN UP

Abstract:

An article is provided that can be used as a heating source for various
applications. The article includes an environmentally friendly gaseous
fuel mixture within a gas cylinder that is both non-corrosive and
refillable. More specifically, the gaseous fuel mixture contains hydrogen
and methane. Methods of using the article as a heating source are also
provided.

Claims:

1. An article comprising: a gaseous fuel mixture comprising (a) hydrogen
in an amount in a range of 30 to 95 volume percent based on a total
volume of the gaseous fuel mixture; and (b) methane in an amount in a
range of 5 to 70 volume percent based on a total volume of the gaseous
fuel mixture; and a refillable gas cylinder comprising a non-corrosive
container and a valve that is connected to the non-corrosive container
and that is suitable for use with a hydrogen-containing gas, wherein the
gaseous fuel mixture is positioned within the non-corrosive container.

9. The article of claim 1, wherein the fuel mixture is free or
essentially free of a solid filler material.

10. The article of claim 1, further comprising a protective guard
surrounding the valve, wherein the protective guard is configured for use
as a handle for carrying the gas cylinder.

11. The article of claim 1, wherein the valve is suitable for discharging
the fuel mixture and for refilling the gas cylinder with additional fuel
mixture after discharging.

12. The article of claim 1, further comprising a gas regulator and a
torch suitable for cutting metal, brazing metal, or soldering metal,
wherein the regulator has a first end connected to the valve and a second
end connected to the torch.

13. The article of claim 12, further comprising a gas cylinder containing
an oxygen-containing gas connected to the torch.

14. A method of providing an environmentally friendly heating source, the
method comprising: providing a refillable gas cylinder comprising a
non-corrosive container and a valve that is connected to the
non-corrosive container and that is suitable for use with a
hydrogen-containing gas; at least partially filling the non-corrosive
container of the gas cylinder with a gaseous fuel mixture, wherein the
fuel mixture comprises a) hydrogen in an amount in a range of 50 to 95
volume percent; and b) methane in an amount in a range of 5 to 50 volume
percent; supplying a heating source, wherein supplying comprises
discharging at least a portion of the gaseous fuel mixture from the
non-corrosive container through the valve and combining the gaseous fuel
mixture with an oxygen-containing gas; and after discharging, adding
additional gaseous fuel mixture to the non-corrosive container through
the valve.

15. The method of claim 14, further comprising using the heating source
to heat metal for a non-welding application.

16. The method of claim 14, further comprising using the heating source
for cutting metal, heating metal, brazing metal, soldering metal,
flame-spraying, or a combination thereof.

17. An article comprising: a gaseous fuel mixture comprising (a) hydrogen
in an amount in a range of 70 to 95 volume percent based on a total
volume of the gaseous fuel mixture; (b) methane in an amount in a range
of 5 to 30 volume percent based on a total volume of the gaseous fuel
mixture; and (c) a mercaptan compound in an amount in a range of 0.1 to
100 parts per million (volume/volume); and a refillable gas cylinder
comprising a non-corrosive container comprising aluminum and a valve that
is connected to the non-corrosive container and that is suitable for use
with a hydrogen-containing gas, wherein the gaseous fuel mixture is
positioned within the non-corrosive container.

19. The article of claim 17, further comprising a gas regulator and a
torch suitable for cutting metal, brazing metal, or soldering metal,
wherein the regulator has a first end connected to the valve and a second
end connected to the torch.

20. The article of claim 19, further comprising a gas cylinder containing
an oxygen-containing gas connected to the torch.

Description:

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Patent
Application No. 61/485,225, filed 12-May 2011, the disclosure of which is
incorporated by reference herein in its entirety.

TECHNICAL FIELD

[0002] The present invention relates to articles that can be used as a
heating source and methods of heating. The articles include a
non-corrosive, refillable gas cylinder containing a gaseous fuel mixture.

BACKGROUND OF THE INVENTION

[0003] Gas cylinders containing a compressed fuel gas are commercially
available in a variety of sizes that can be used as a source of heat
(i.e., heating source). Gas cylinders that are of a portable size are
often not reusable (i.e., refillable). After the compressed fuel gas has
been used as a heating source, the gas cylinders can present an
environmental hazard if they are not disposed of properly. More
specifically, the gas cylinders often contain some residual fuel (i.e.,
residual compressed gas) inside after normal use. If the gas cylinders
undergo corrosion, the residual fuel can be released. This release can
pose both an environmental problem and a potential fire or explosion
hazard.

[0004] Fuel gases are often used to heat metal in various metallurgical
applications. One commonly used fuel gas for fusion welding and brazing
is acetylene. Acetylene has a number of drawbacks as a fuel gas,
particularly for use in portable gas cylinders. It is explosive if the
pressure exceeds about 15 pounds per square inch (psi). For this reason,
acetylene is usually dissolved in acetone or another organic solvent to
improve its stability. Further, various porous filler materials are
typically placed in gas cylinders used with acetylene to further improve
stability. The addition of these porous materials can adversely impact
the total weight of the gas cylinder containing acetylene. Further,
addition of these porous materials can create a disposal problem because
the used porous materials may be considered a hazardous waste.

SUMMARY OF THE INVENTION

[0005] An article is provided that can be used, when combined with an
oxygen-containing gas, as a heating source for various applications,
particularly for non-welding metallurgical applications. The article
includes a gas cylinder containing an environmentally friendly gaseous
fuel mixture. The gas cylinders are both non-corrosive and refillable.
More specifically, the gaseous fuel mixture contains hydrogen and
methane. Methods of using the article as a heating source are also
provided.

[0006] In a first aspect an article is provided that includes a gaseous
fuel mixture and a refillable gas cylinder. The gaseous fuel mixture
comprises (a) hydrogen in an amount in a range of 30 to 95 volume percent
based on a total volume of the gaseous fuel mixture and (b) methane in an
amount in a range of 5 to 70 weight percent based on the total volume of
the gaseous fuel mixture. The gas cylinder has (a) a non-corrosive
container and (b) a valve that is connected to the non-corrosive
container and that is suitable for use with a hydrogen-containing gas.
The gaseous fuel mixture is positioned within the non-corrosive container
of the gas cylinder.

[0007] In a second aspect, a heating method is provided that can be
environmentally friendly. The method includes providing a refillable gas
cylinder having a non-corrosive container and a valve that is connected
to the non-corrosive container and that is suitable for use with a
hydrogen-containing gas. The method further includes at least partially
filling the non-corrosive container of the gas cylinder with a gaseous
fuel mixture that contains both hydrogen and methane. Hydrogen is present
in the gaseous fuel mixture in an amount in a range of 30 to 95 volume
percent based on a total volume of the gaseous fuel mixture. Methane is
present in the gaseous fuel mixture in an amount in a range of 5 to 70
volume percent based on the total volume of the gaseous fuel mixture. The
method still further includes supplying a heating source, wherein
supplying includes discharging at least a portion of the gaseous fuel
mixture from the non-corrosive container through the valve and combining
the gaseous fuel mixture with an oxygen-containing gas. After
discharging, the method yet further includes adding additional gaseous
fuel mixture to the non-corrosive container through the valve.

[0008] In a third aspect, an article is provided that includes a gaseous
fuel mixture and a refillable gas cylinder. The gaseous fuel mixture
comprises (a) hydrogen in an amount in a range of 70 to 95 volume percent
based on a total volume of the gaseous fuel mixture, (b) methane in an
amount in a range of 5 to 30 weight percent based on the total volume of
the gaseous fuel mixture, and (c) a mercaptan compound in an amount less
than 0.1 to 100 parts per million (volume/volume). The gas cylinder has
(a) a non-corrosive container comprising aluminum and (b) a valve that is
connected to the non-corrosive container and that is suitable for use
with a hydrogen-containing gas. The gaseous fuel mixture is positioned
within the non-corrosive container of the gas cylinder.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Embodiments of the invention are described by way of example, with
reference to the accompanying drawings, in which:

[0010] FIG. 1 shows a schematic drawing of an exemplary embodiment of a
refillable and non-corrosive gas cylinder containing a gaseous fuel
mixture.

DETAILED DESCRIPTION

[0011] An article is provided that can be used as a heating source when
combined with an oxygen-containing gas. Additionally, a heating method is
provided using the articles described herein. The article and method can
overcome many of the environmental issues associated with current
portable heating sources and, in particular, those associated with the
use of acetylene gas. The article and method are particularly useful for
various non-welding metallurgical applications.

[0012] In a first aspect an article is provided that include a gaseous
fuel mixture and a refillable gas cylinder. The gaseous fuel mixture
comprises (a) hydrogen in an amount in a range of 30 to 95 volume percent
based on a total volume of the gaseous fuel mixture and (b) methane in an
amount in a range of 5 to 70 weight percent based on the total volume of
the gaseous fuel mixture. The gas cylinder has (a) a non-corrosive
container and (b) a valve that is connected to the non-corrosive
container and that is suitable for use with a hydrogen-containing gas.
The gaseous fuel mixture is positioned within the non-corrosive container
of the gas cylinder.

[0013] FIG. 1 is a schematic drawing of one such article. The article
includes a gas cylinder 10 that includes both the non-corrosive container
20 and a valve 30 that is connected to the non-corrosive container 20.
The gaseous fuel mixture 40 is positioned within the non-corrosive
container 20. The gaseous fuel mixture can be charged into the
non-corrosive container 20 of the gas cylinder 10 and discharged from the
gas cylinder 10 through the valve 30.

[0014] The gaseous fuel mixture, which can be used as a source of heat
when combined with an oxygen-containing gas, contains a mixture of
hydrogen and methane. When used as a heating source, the gaseous fuel
mixture combusts in the presence of oxygen to produce carbon dioxide and
water. There are few, if any, other combustion products. That is, the
gaseous fuel mixture burns cleanly in the presence of oxygen. Both the
gaseous fuel mixture and the combustion products are naturally present in
the atmosphere and pose few, if any, environmental or health concerns.
Stated differently, both the gaseous fuel mixture and its reaction
products do not contaminate water, soil, or the atmosphere.

[0015] The gaseous fuel mixture typically contains 30 to 95 volume percent
hydrogen and 5 to 70 volume percent methane based on a total volume of
the gaseous fuel mixture. If a lower amount of methane is included in the
gaseous fuel mixture, a well formed flame can be difficult to obtain in
the presence of oxygen. That is, the flame formed after mixing of the
gaseous fuel mixture with an oxygen-containing gas can lift away from the
tip of a torch. Such a flame is difficult to control or use effectively
in many applications. On the other hand, if a higher amount of methane is
included in the gaseous fuel mixture, the cost of the gaseous fuel
mixture tends to increase and the amount of carbon dioxide formed in the
combustion products increases.

[0017] The hydrogen in the gaseous fuel mixture can be from any suitable
source and can have any desired purity. Hydrogen is often a by-product
produced when refining propane. The purity can be dependent on the
particular application. The purity for hydrogen is often selected to be
at least 99.95 percent pure, at least 99.99 percent pure, at least 99.995
percent pure, or at least 99.999 percent pure. Standard industrial grade
hydrogen, which usually has a purity of at least 99.95 percent, can
contain, for example, up to 10 parts per million (volume/volume) carbon
dioxide, up to 10 parts per million (volume/volume) carbon monoxide, up
to 10 parts per million (volume/volume) oxygen, up to 400 parts per
million (volume/volume) nitrogen, and up to 34 parts per million
(volume/volume) water. Hydrogen is commercially available in different
purity levels from multiple suppliers.

[0018] The methane in the gaseous fuel mixture can be from any suitable
source and can have any desired purity. Methane is a by-product of
refining petroleum and can be found naturally. The purity for methane is
often selected to be at least 99.0 percent pure, at least 99.9 percent
pure, at least 99.97 percent pure, or at least 99.99 percent pure.
Methane that is at least 99.0 percent pure, which is often referred to as
a chemically pure grade, can contain impurities such as, for example, up
to 150 parts per million (volume/volume) ethane, up to 5000 parts per
million (volume/volume), up to 150 parts per million (volume/volume)
oxygen, up to 150 parts per million (volume/volume) other hydrocarbons,
and up to 3 parts per million (volume/volume) water. Methane is
commercially available in different purity levels from multiple
suppliers.

[0019] The gaseous fuel mixture containing both hydrogen and methane
typically has less than 1000 parts per million (volume/volume) carbon
monoxide and less than 1000 parts per million (volume/volume) carbon
dioxide. The presence of either of these gases can result in the
formation of a caustic environment when the gaseous fuel mixture is used
as a heating source. Low levels of carbon monoxide are desired because of
its toxicity. In many embodiments, the concentration of both carbon
monoxide and carbon dioxide in the gaseous fuel mixture is less than 500
parts per million (volume/volume), less than 200 parts per million
(volume/volume), less than 100 parts per million (volume/volume), less
than 50 parts per million (volume/volume), less than 20 parts per million
(volume/volume), or less than 10 parts per million (volume/volume).

[0020] A mercapto-containing compound may be added to the gaseous fuel
mixture to provide an odor sufficient to alert humans nearby of the
presence of the gaseous fuel mixture. This can be helpful, for example,
if a leak develops in the gas cylinder used to store the gaseous fuel
mixture or if the valve of the gas cylinder is accidently opened or left
opened. Any suitable mercapto-containing compound can be used. The
strength of the odor of these compounds is typically related to their
molecular weight. That is, mercapto-containing compounds of lower
molecular weight tend to be more volatile. In some embodiments, the
mercaptan-containing compound is an alkyl mercaptan with the alkyl group
having 1 to 10 carbon atoms, 1 to 6 carbon atoms, 1 to 4 carbon atoms, 1
to 3 carbon atoms, or 1 to 2 carbon atoms. Some specific alkyl mercaptan
compounds include methyl mercaptan and ethyl mercaptan.

[0021] The human detection of many alkyl mercaptan compounds such as
methyl mercaptan can be less than 1 parts per million (volume/volume).
Thus, only a small amount of the mercapto-containing compound such as an
alkyl mercaptan is needed in the gaseous fuel mixture to provide an
alert. The gaseous fuel mixture can contain up to 100 part per million
(volume/volume) mercapto-containing compound based on the total volume of
the gaseous fuel mixture. For example, the mercapto-containing compound
can be present in an amount up to 80 parts per million (volume/volume),
up to 75 parts per million (volume/volume), up to 50 parts per million
(volume/volume), up to 25 parts per million (volume/volume), up to 20
parts per million (volume/volume), or up to 10 parts per million
(volume/volume). In some examples, the mercapto-containing compound is
present in an amount in a range of 0.1 to 100 parts per million
(volume/volume), a range of 0.1 to 50 parts per million (volume/volume),
in a range of 0.1 to 25 parts per million (volume/volume), in a range of
0.1 to 20 parts per million (volume/volume), in a range of 1 to 20 parts
per million (volume/volume), in a range of 0.1 to 10 parts per million
(volume/volume), in a range of 1 to 10 parts per million (volume/volume),
in a range of 0.1 to 5 parts per million (volume/volume), in a range of 1
to 5 parts per million (volume/volume), in a range of 0.1 to 2 parts per
million (volume/volume), in a range of 0.1 to 1 parts per million
(volume/volume), in a range of 0.1 to 0.5 parts per million
(volume/volume), or in a range of 0.1 to 0.2 parts per million
(volume/volume).

[0022] The gaseous fuel mixture can be obtained from PRO-CYL LLC under the
trade designation HYDRO MIX.

[0023] The gaseous fuel mixture is typically free or essentially free of
various organic solvents such as, for example, acetone, dimethyl
formamide, N-methylpyrrolidinone, or mixtures thereof. These solvents are
typically used with acetylene fuels but are not needed for the gaseous
fuel mixtures described herein. When used in reference to acetylene or to
organic solvents typically present when acetylene is used as a fuel gas,
the term "essentially free" means less than 2 volume percent, less 1
volume, less than 0.5 volume percent, less than 0.1 volume percent (1000
parts per million), less than 0.05 volume percent (500 parts per
million), less than 0.01 volume percent (100 parts per million), less
than 50 parts per million (volume/volume), or less that 20 parts per
million (volume/volume) based on a total weight of the gaseous fuel
mixture. Depending on the purity of the methane used in the gaseous fuel
mixture, there can be trace levels of other hydrocarbons present.

[0024] The contents within the non-corrosive container are typically free
or essentially free of various solid filler materials such as various
stabilizers such a diatomaceous earth, cellulosic wood fiber, and the
like. No solid reactants are present in the gas cylinders for the
production of the gaseous fuel mixture. As used herein in reference to
filler materials, the term "essentially free" means less than 2 percent
by weight, less than 1 percent by weight, less than 0.5 percent by
weight, less than 0.1 percent by weight, less than 0.05 percent by
weight, or less than 0.001 percent by weight based on a total weight of
the contents within the non-corrosive container. Stated differently, the
stabilizers needed with other commonly used heating sources such as
acetylene are not included in the current gaseous fuel mixtures and
typically are not present within the non-corrosive gas cylinder. This is
particularly advantageous because the amount of residual gas remaining in
a spent gas cylinder can be less in the absence of the stabilizers.
Additionally, the absence of the solid filler materials can lighten the
weight of the article considerably. For example a gas cylinder having a
diameter of about 6.9 inches (17.5 cm) and a length of about 33.1 inches
(84.1 cm) that is filled with the gaseous fuel mixture described herein
typically weighs in a range of 15 to 20 pounds. A comparably sized gas
cylinder filled with acetylene weighs about twice this amount.

[0025] The gaseous fuel mixture is provided within a gas cylinder for use
as a heating source. The gas cylinder is both refillable and
non-corrosive. The gas cylinder includes both a non-corrosive container
and a valve that is connected to the non-corrosive container. The valve
is suitable for use with a hydrogen-containing gas and suitable for
refilling. The gaseous fuel mixture is placed within the non-corrosive
container.

[0026] Although any suitable gas cylinder could be used, it is highly
desirable to provide a heating source that is environmentally friendly.
One aspect of being environmentally friendly is using gas cylinders that
are refillable. Many commonly available gas cylinders, particularly those
available for use as portable heating sources (e.g., those weighing less
than 10 pounds, less than 5 pounds, or less than 1 pound) such as those
commonly used for propane and propylene, are not refillable. After use,
the non-refillable gas cylinders are typically disposed of in a land fill
or other disposal site. Refillable gas cylinders can be advantageously
used to reduce the amount of solid waste generated through the use of the
gaseous fuel mixture.

[0027] Another aspect of being environmentally friendly is using a gas
cylinder that is non-corrosive (i.e., not corrodible under typical use
conditions). Many commonly used gas cylinders are constructed of metals
such as carbon steel that can undergo corrosion. Corrosion may be caused
from the outside of the gas cylinder, through contact with water, salts,
carbon dioxide, and the like. Corrosion of the gas cylinders can be a
problem aesthetically. More importantly, however, when corrosion occurs,
any residual fuel within the gas cylinders can leach into the soil and/or
groundwater creating environmental concerns. Corroded gas cylinders have
been associated with explosions. That is, the residual gas in the gas
cylinders can leak out of the gas cylinders and react violently upon
exposure to air or upon exposure to other chemicals that may be present
in the environment.

[0028] The amount of gas cylinder corrosion is typically controlled by
providing an outer coating to protect a corrodible metal (i.e., a metal
that can undergo corrosion under typical use conditions). That is, the
outer coating reduces the likelihood of corrosion by minimizing exposure
of the surface of the gas cylinder's corrodible portions to an oxidizing
environment. This outer coating can be, for example, a layer of paint or
a layer of a polymeric material. The outer coating is typically selected
to be tough or resistant to removal when scratched or bumped. Although
the outer coating can reduce corrosion, such coatings rarely totally
prevent corrosion because, over time, portions of the outer coating are
removed through use and the metal becomes exposed.

[0029] Thus, the gaseous fuel mixture described herein is provided within
a gas cylinder constructed out of non-corrosive materials (i.e., metals
that do not undergo corrosion under typical use conditions although an
oxidized layer may be present on the outer surface). Any metal or metal
alloy can be selected that is non-corrosive and that can be fabricated
for use as a gas cylinder. The non-corrosive container of the gas
cylinder can be fabricated, for example, from stainless steel, nickel or
a nickel alloy, titanium or a titanium alloy, or aluminum or an aluminum
alloy. In practice, however, aluminum or an aluminum alloy is typically
selected based on cost considerations. In addition to be non-corrosive,
gas cylinders fabricated from aluminum or an aluminum alloy tend to be
significantly lighter than comparably sized gas cylinders fabricated from
carbon steel. For example, gas cylinders of aluminum tend to be 40 to 60
percent lighter than comparably sized gas cylinders of carbon steel.
Aluminum can be used to provide a gas cylinder that is non-corrosive,
lightweight, recyclable, strong, and economical.

[0030] The gaseous fuel mixture is typically introduced into the
non-corrosive (i.e., non-corrodible) container of the gas cylinder
through the valve. When used as a heating source, the gaseous fuel
mixture is discharged through the same valve and combined with oxygen.
After discharging at least a portion of the gaseous fuel mixture from the
non-corrodible container, additional gaseous fuel mixture can be
introduced into the non-corrodible container through the valve.

[0031] The gas cylinder can have any desired size. Most of the gas
cylinders have a length that is greater than the diameter. The diameter
can be, for example, at least 7.6 cm (3 inches), at least 10.2 cm (4
inches), or at least 12.7 cm (5 inches) and can extend up to 25.4 cm (10
inches), up to 17.8 cm (7 inches), up to 22.9 cm (9 inches), or even
more. For example, the diameter can be in a range of 7.6 to 25.4 cm (3 to
10 inches), in a range of 7.6 to 20.3 cm (3 to 8 inches), or in a range
of 7.6 to 15.2 cm (3 to 6 inches). The length can be up to 152.4 cm (60
inches) or even longer, up to 127 cm (50 inches), up to 101.6 cm (40
inches), or up to 76.2 cm (30 inches). The length is often at least 20.3
cm (8 inches), at least 25.4 cm (10 inches), at least 30.5 cm (12
inches), or at least 38.1 cm (15 inches). For example, the length can be
in a range of 20.3 to 152.4 cm (8 to 60 inches), in a range of 229.5 to
140 cm (9 to 55 inches), in a range of 25.4 to 127 cm (10 to 50 inches),
or in a range of 25.4 to 101.6 cm (10 to 40 inches). Some cylinders have
a diameter of 7.6 cm (3 inches) to 15.2 cm (6 inches) such as, for
example, those referred to in the industry as MC cylinders and B
cylinders. Suitable gas cylinders such as those constructed of aluminum
or an aluminum alloy can be obtained, for example, from CYL-TEC of
Aurora, Ill.

[0032] In some embodiments, the gas cylinder filled with the gaseous fuel
mixture is light enough to be carried by hand. In other embodiments, the
cylinders must be transported using a cart and can be moved easily from
one location to another for use. In still other embodiments, one or more
gas cylinders can be positioned at a first location and the gaseous fuel
mixture is transferred to a second location of use through a system of
pipes or flexible tubing. For example, group of gas cylinders (e.g., 6
gas cylinders or 12 gas cylinders) containing the gaseous fuel mixture
can be connected together through a manifold at a first location and then
transferred through a system of pipes or flexible tubing to the second
location. As another example, a plurality of gas cylinders containing the
gaseous fuel mixture can be stored on a trailer such as a truck trailer
and the gaseous fuel mixture can be transferred from the trailer to the
use location through a system of pipes of flexible tubing to the second
location. The gas cylinder includes a valve that is suitable for use with
a hydrogen-containing gas.

[0033] This valve is often fitted with reverse threads (i.e., left-handed
threads) and with a pressure-release feature. The gas fuel mixture is
introduced and discharged through this valve. The valve functions as an
on/off valve and as a course regulator of the flow rate.

[0034] The non-corrosive container of the gas cylinder can be filed with
any suitable amount of the gaseous fuel mixture. The initial pressure is
typically selected based on the specifications for the particular gas
cylinder and depends on such factors as the cylinder size, thickness of
the walls of the container, and the specific composition of the gaseous
fuel mixture. The pressure of filling the gaseous fuel mixture depends
upon the capacity of the container. For example, the initial pressure can
be at least 10,340 kPa (1500 psi), at least 13,790 kPa (2000 psi), at
least 15,278 kPa (2216 psi), at least 17,237 kPa (2500 psi), or at least
20,684 kPa (3000 psi). If the gas cylinder is constructed of aluminum or
an aluminum alloy, the initial pressure is often close to 15,278 kPa
(2216 psi). Other than a mercapto-containing compound and trace
impurities that may be present in the hydrogen and the methane, no other
compound or material is typically added to the gas cylinders besides
hydrogen and methane.

[0035] A gas flow regulator is typically added to the exit side of the
valve (i.e., the side of the valve that is not directly connected to the
gas cylinder) and is used to better control the flow rate of the gaseous
fuel mixture discharged from the gas cylinder. Suitable regulators
include, for example, those commercially available under the trade
designation CGA 350 from various suppliers.

[0036] A torch is often added on the exit side of the regulator (i.e., the
side of the regulator that is opposite the valve of the gas cylinder).
That is, the regulator has a first end that is connected to the valve and
a second end that is connected to the torch. A flexible hose, such as
those commonly used in the welding industry, is typically used to join
the torch to the regulator. The torch and, in particular, the torch tip
are often selected based on the particular use of the gaseous fuel
mixture as a heating source. The torch is usually configured to mix the
gaseous fuel mixture with an oxygen-containing source (e.g., ambient air,
compressed air, or compressed oxygen). Torches may include additional
optional safety features such as check valves that allow flow in a single
direction.

[0037] The oxygen combined with the gaseous fuel mixture to provide both a
flame and heat can be a component of atmospheric air or can be provided
as a compressed gas (e.g., air or oxygen) in another gas cylinder.
Usually, the oxygen is supplied from another gas cylinder that is
connected to the torch through a regulator and a flexible hose such as
those commonly used in the welding industry. Torches connected to
compressed oxygen cylinders often provide a higher temperature flame than
those produced using atmospheric air as the oxidant. That is, a higher
temperature flame can result from the combustion of the gaseous fuel
mixture with oxygen rather than air. Stated differently, the
concentration of oxygen mixed with the gaseous fuel mixture can be used
to regulate the temperature of the flame. The flame can be an oxidizing
flame when the amount of oxygen exceeds the amount of the gaseous fuel
mixture, can be a neutral flame when the amount of oxygen is roughly
equal to the amount of the gaseous fuel mixture, or can be a reducing
flame when the amount of oxygen is less than the amount of the gaseous
fuel mixture. The oxidizing flames tend to be of the highest temperature
(e.g., about 3480° C. (6300° F.)). Neutral flames are often
desirable for cutting purposes; however, reducing flames can also be used
for cutting such as thin materials where less distortion is desired.
Reducing flames, which tend to be the coolest (e.g., about 3200°
C. (5800° F.)), are often used for soldering.

[0038] Various tips can be used with the torches. The size and shape of
the tip are typically selected based on the particular application. For
example, for cutting metal, the tip size is usually selected based on the
thickness of the metal being cut. Various tips are commercially available
from a variety of suppliers such as, for example, PRO-CYL LLC. Torch tips
that draw ambient air as the oxygen source are commonly used in the
heating and plumbing industry.

[0039] The gas cylinder may be equipped with additional safety features.
For example, a polymeric sleeve can be positioned around at least a
portion of the exterior of the gas cylinder such as around the
non-corrosive container. This polymeric sleeve can protect the gas
cylinder from become scratched or scraped when positioned adjacent to
other gas cylinders.

[0040] The gas cylinder can be further equipped with a protective guard
around the valve that helps minimize the accidental opening of the valve
or that helps minimize the accidental dislodging or removal of the valve
in the event that the gas cylinder falls from its upright position. For
gas cylinders that are portable, the protective guard can be designed to
provide a handle or position for carrying the gas cylinder.

[0041] In another aspect, an article is provided that includes a gaseous
fuel mixture and a refillable gas cylinder. The gaseous fuel mixture
comprises (a) hydrogen in an amount in a range of 70 to 95 volume percent
based on a total volume of the gaseous fuel mixture, (b) methane in an
amount in a range of 5 to 30 weight percent based on the total volume of
the gaseous fuel mixture, and (c) a mercaptan compound in an amount less
than 0.1 to 100 parts per million (volume/volume). The gas cylinder has
(a) a non-corrosive container comprising aluminum and (b) a valve that is
connected to the non-corrosive container and that is suitable for use
with a hydrogen-containing gas. The gaseous fuel mixture is positioned
within the non-corrosive container of the gas cylinder.

[0042] The gas cylinders are often refillable, recyclable, lightweight
(e.g., lighter than steel or other commonly used gas cylinders), and
non-corrosive. The gaseous fuel mixture is environmentally friendly.

[0043] In yet another aspect, an environmentally friendly heating method
is provided. The method includes providing a refillable gas cylinder
having a non-corrosive container and a valve that is connected to the
non-corrosive container and that is suitable for use with a
hydrogen-containing gas. The method further includes at least partially
filling the non-corrosive container of the gas cylinder with a gaseous
fuel mixture that contains both hydrogen and methane. Hydrogen is present
in the gaseous fuel mixture in an amount in a range of 30 to 95 volume
percent based on a total volume of the gaseous fuel mixture. Methane is
present in the gaseous fuel mixture in an amount in a range of 5 to 70
volume percent based on the total volume of the gaseous fuel mixture. The
method yet further includes supplying a heating source, wherein supplying
includes discharging at least a portion of the gaseous fuel mixture from
the non-corrosive container of the gas cylinder through the valve and
combining the gaseous fuel mixture with an oxygen-containing gas. After
discharging, the method still further includes adding additional gaseous
fuel mixture to the non-corrosive container of the gas cylinder through
the valve.

[0044] In this method, the gas cylinder is the same as described above.
Additionally, the gaseous fuel gas mixture is the same as described
above. The gas cylinder is designed such that it can be refilled multiple
times. That is, the gaseous fuel mixture initially introduced into the
gas cylinder can be used as a heating source upon being discharged from
the gas cylinder and combined with an oxygen-containing gas. After
discharging, additional gaseous fuel mixture can be introduced into the
gas cylinder to replace the gaseous fuel mixture that was discharged.
This newly introduced gaseous fuel mixture can subsequently be used as a
heating source. The charging (i.e., introduction of gaseous fuel mixture
into the gas cylinder) and discharging (i.e., removal of gaseous fuel
mixture from the gas cylinder) steps may occur multiple times. For
example, the charging and discharging steps can occur at least 10 times,
at least 20 times, at least 50 times, or at least 100 times, so long as
adequate safety testing is performed on the gas cylinders and the gas
cylinders continue to satisfy the appropriate safety standards.

[0045] The gaseous fuel mixture generates heat when mixed with an
oxygen-containing gas and combusted. The combustion reaction generates
heat and allows the gaseous fuel mixture to function as a heat source.
The heat source can be used to perform a variety of non-welding
metallurgical tasks such as heating metal, cutting metal, brazing metal,
soldering metal, flame spraying, and the like. The heat source also can
be used under appropriate conditions for cooking purposes (e.g., with a
stove or grill) or for providing heat to a space such as a room.

[0046] In one example, the combination of gaseous fuel mixture and oxygen
is used as a heating source for cutting metal. This refers to severing
the metal. Specialized cutting torch heads are typically used. Currently,
cutting is often performed using acetylene. Acetylene cutting tends to be
dirty, and the cutting tip is especially susceptible to becoming clogged
with debris. The gaseous fuel mixture described herein tends to burn
cleaner than acetylene and is more desirable where contamination of the
metal that is being cut needs to be minimized. In some cutting
applications, the metal is steel or another ferrous-containing metal.

[0047] In other examples, the combination of gaseous fuel mixture and
oxygen is used as a heating source for brazing metal or for soldering
metal. Brazing and soldering both refer to metal joining processes. A
filler metal is usually heated above its melting point and then
distributed between two or more close-fitting metal parts by capillary
action. The filler metal is often flowed over one part (know as wetting)
and then cooled to join the two parts together. The temperature
associated with soldering is lower than that associated with brazing.
More specifically, the American Welding Society defines soldering as
occurring at temperatures below 840° F. (450° C.) while
brazing occurs at temperature greater than 840° F. (450°
C.). That is, the filler metal used in soldering has a melting point less
840° F. (450° C.) than while the filler metal used for
brazing has a melting point greater than 840° F. (450° C.).
Suitable filler materials for both soldering and brazing are commercially
available from multiple suppliers include, for example, PRO-CYL LLC and
from UNITED BLAZING under the trade designation BRAZECRAFT and
SOLDERCRAFT. A commonly used brazing filler material is known as Low
Fuming Bronze (LFB), which melts at about 880° C. (1620°
F.). A commonly used soldering filler material is STAYBRITE 8. With
brazing or soldering, the base metal being joined is heated but not to a
temperature sufficient to cause melting (i.e., the base metals are not
fused together). Steel, for example, melts at about 1150° C.
(2100° F.). The color of the brazing filler material is often
different than that of the metal parts joined together. The cohesion of
the brazing material to the metal parts joined together results in the
joint formation.

[0048] In still other examples, the combination of gaseous fuel mixture
and oxygen is used to heat metal such as pre-heating metal prior to
performing various tasks such as brazing, soldering, or cutting.
Alternatively, the heating can be coupled with a controlled cooling
process to prevent the formation of cracks in metals after being
subjected to various high temperature processes.

[0049] In yet other examples, the combination of gaseous fuel mixture and
oxygen is used as a heating source for flame spraying. Flame spraying
refers to a method of coating a metal substrate. The coating material,
which is often in the form of a wire or powder of metal or ceramic
material, is heated to its melting point and formed into droplets. The
droplets are accelerated by high pressure air streams and sprayed onto
the surface of the metal substrate.

[0050] The gaseous fuel mixture combined with an oxygen-containing gas is
typically not a suitable heat source for welding. Unlike the flame
produced by the combination of oxygen and acetylene, the flame resulting
from the combination of oxygen and the gaseous fuel mixture described
herein tends to be fairly uniform in temperature. There is no inner cone
region that is as hot as that present in an acetylene flame (i.e., in the
blue inner cone region of the acetylene flame). There is no localized
region as in the acetylene flame that is hot enough to melt metals such
as steel. When used for welding purposes, the joints formed tend to be
weak compared to those formed with an acetylene flame.

[0051] Even though the flame produced by combustion of the gaseous fuel
mixture is not suitable for welding, it is particularly well suitable for
many non-welding applications involving the joining of metal parts or the
treatment of metal surfaces. The flame produced by the combustion of the
gaseous fuel mixture is particularly well suited for non-welding
applications such as cutting, brazing, and soldering because of its lower
temperature compared to acetylene and because of its cleaner nature than
acetylene. The flame tends to be quite uniform in temperature throughout
and this uniformity is useful when used in applications where excessive
heat can cause damage to the metal being joined.

[0052] After the gaseous fuel mixture has been discharged (e.g., partially
discharged or completely discharged) from the gas cylinder, the
discharged gas cylinder can be returned to the vendor or to a refilling
station. The vender or the refilling station can then recharge (i.e.,
refill) the gas cylinder with additional gaseous fuel mixture. In certain
embodiments, the exterior of the gas cylinder may include information
about the location of these refilling stations or can include a website
address with such information. In some instances, the vendor, the
refilling station, or both obtains a license from the manufacturer to
recharge the gas cylinder with the gaseous fuel mixture.

[0053] The refillable nature of the currently described heating sources
offer several environmental and safety advantages over commonly used
heating sources. For example, using refillable gas cylinders can diminish
the number of gas cylinders that end up as solid waste. The non-corrosive
nature of the gas cylinders lowers the risk of contamination if residual
gaseous fuel mixture remains in gas cylinders or if gas cylinders are
disposed of (perhaps accidentally) in an improper manner. When the useful
lifetime of the gas cylinder is reached, it can usually be recycled,
particularly if it is made of aluminum. This also can lead to reduced
solid waste compared to many currently used gaseous heating sources.

[0054] The gaseous fuel mixture can be combusted to provide a flame with
minimal soot or that is free of soot. A torch containing a mixture of
oxygen and the gaseous fuel mixture is typically easy to light. No
special torches are needed. That is, industrial standard torches and
torch tips can be used without modification.

[0055] Additionally, the flame noise is relatively low because of the
relatively low flow rates (i.e., the relatively low pressure settings on
the regulator) of the gaseous fuel mixtures that are needed to sustain a
flame. Lower flow rates tend to correlate with lower noise levels (i.e.,
lower decibels). For example, to cut a steel plate having a thickness of
2.54 cm (1 inch), a fuel pressure of 34.5 to 68.9 kPa (5 to 10 psi) can
be used in combination with an oxygen pressure of 275.6 to 344.5 kPa (40
to 50 psi) to cut at a speed of 35.5 to 50.8 cm per minute (14 to 20
inches per minute). In another example, to cut a steel plate having a
thickness of 25.4 cm (10 inches), a fuel pressure of 68.9 to 103.4 kPa
(10 to 15 psi) can be used in combination with an oxygen pressure of
413.4 to 482.3 kPa (60 to 70 psi) to cut at a speed of 10.2 to 15.2 cm
per minute (4 to 6 inches per minute).

[0056] Various items are provided that are articles or method of heating.

[0057] Item 1 is an article is provided that includes a gaseous fuel
mixture and a refillable gas cylinder. The gaseous fuel mixture comprises
(a) hydrogen in an amount in a range of 30 to 95 volume percent based on
a total volume of the gaseous fuel mixture and (b) methane in an amount
in a range of 5 to 70 weight percent based on the total volume of the
gaseous fuel mixture. The gas cylinder has (a) a non-corrosive container
and (b) a valve that is connected to the non-corrosive container and that
is suitable for use with a hydrogen-containing gas. The gaseous fuel
mixture is positioned within the non-corrosive container of the gas
cylinder.

[0060] Item 4 is the article of any one of items 1 to 3, wherein the
gaseous fuel mixture further comprises a mercapto-containing compound.

[0061] Item 5 is the article of item 4, wherein the mercapto-containing
compound is methyl mercaptan.

[0062] Item 6 is the article of any one of items 1 to 5, wherein the
non-corrosive container comprises aluminum or an aluminum alloy.

[0063] Item 7 is the article of any of one of items 1 to 6, wherein the
gas cylinder further comprises polymeric sleeve arranged on a portion of
container.

[0064] Item 8 is the article of any one of items 1 to 7, wherein the fuel
mixture is free or essentially free of acetylene, acetone, dimethyl
formamide, N-methylpyrrolidinone, or mixtures thereof.

[0065] Item 9 is the article of any one of items 1 to 8, wherein the fuel
mixture is free or essentially free of a solid filler material.

[0066] Item 10 is the article of any one of items 1 to 9, further
comprising a protective guard surrounding the valve, wherein the
protective guard is configured for use as a handle for carrying the gas
cylinder.

[0067] Item 11 is the article of any one of items 1 to 10, wherein the
valve is suitable for discharging the fuel mixture and for refilling the
gas cylinder with additional fuel mixture after discharging.

[0068] Item 12 is the article of any one of items 1 to 11, further
comprising a gas regulator and a torch suitable for cutting metal,
brazing metal, or soldering metal, wherein the regulator has a first end
connected to the valve and a second end connected to the torch.

[0069] Item 13 is the article of item 12, further comprising a gas
cylinder containing an oxygen-containing gas connected to the torch.

[0070] Item 14 is a method of heating that can be environmentally
friendly. The method includes providing a refillable gas cylinder having
a non-corrosive container and a valve that is connected to the
non-corrosive container and that is suitable for use with a
hydrogen-containing gas. The method further includes at least partially
filling the non-corrosive container of the gas cylinder with a gaseous
fuel mixture that contains both hydrogen and methane. Hydrogen is present
in the gaseous fuel mixture in an amount in a range of 30 to 95 volume
percent based on a total volume of the gaseous fuel mixture. Methane is
present in the gaseous fuel mixture in an amount in a range of 5 to 70
volume percent based on the total volume of the gaseous fuel mixture. The
method still further includes supplying a heating source, wherein
supplying includes discharging at least a portion of the gaseous fuel
mixture from the non-corrosive container through the valve and combining
the gaseous fuel mixture with an oxygen-containing gas. After
discharging, the method yet further includes adding additional gaseous
fuel mixture to the non-corrosive container through the valve.

[0071] Item 15 is the method of item 14, further comprising using the
heating source to heat metal for a non-welding application.

[0072] Item 16 is the method of item 15, wherein the non-welding
application is cutting, brazing, soldering, flame spraying, or a
combination thereof.

[0073] Item 17 is an article is provided that includes a gaseous fuel
mixture and a refillable gas cylinder. The gaseous fuel mixture comprises
(a) hydrogen in an amount in a range of 70 to 95 volume percent based on
a total volume of the gaseous fuel mixture, (b) methane in an amount in a
range of 5 to 30 weight percent based on the total volume of the gaseous
fuel mixture, and (c) a mercaptan compound in an amount less than 0.1 to
100 parts per million (volume/volume). The gas cylinder has (a) a
non-corrosive container comprising aluminum and (b) a valve that is
connected to the non-corrosive container and that is suitable for use
with a hydrogen-containing gas. The gaseous fuel mixture is positioned
within the non-corrosive container of the gas cylinder.

[0075] Item 19 is an article of item 17 or 18, further comprising a gas
regulator and a torch suitable for cutting metal, brazing metal, or
soldering metal, wherein the regulator has a first end connected to the
valve and a second end connected to the torch.

[0076] Item 20 is the article of item 19, further comprising a gas
cylinder containing an oxygen-containing gas connected to the torch.

[0077] Item 21 is the article of any one of items 17 to 20, wherein the
gas cylinder is recyclable, and lightweight and wherein the gaseous fuel
mixture is environmentally friendly.

[0078] Item 22 is a method of using the article of any one of items 1 to
13 or items 17 to 21 for heating metal, brazing metal, or a combination
thereof.

[0079] Item 23 is the method of item 22 wherein the heating metal, brazing
metal, or a combination thereof is performed on component of a heating,
ventilation, or air conditioning system.

[0080] Item 24 is the article of any one of items 1 to 13 or items 17 to
21, wherein the gas cylinder has a diameter of 7.6 cm (3 inches) to 15.2
cm (6 inches).

EXAMPLES

Example 1

Cutting

[0081] A gaseous fuel mixture containing 90 volume percent hydrogen and 10
volume percent methane was used in combination with oxygen for cutting.
The oxygen was dispensed at a rate of 30 cubic feet per hour and the
gaseous fuel mixture was dispensed at a rate of 2 cubic feet per hour.
The torch had a SMITH #1 tip. A sample of 0.5 inch thick A-36 mild steel
plate was cut at a rate of 24 inches per minute using the torch.

[0083] A gaseous fuel mixture containing 90 volume percent hydrogen and 10
volume percent methane was used in combination with oxygen for brazing.
The oxygen was dispensed at a rate of 30 cubic feet per hour and the
gaseous fuel mixture was dispensed at a rate of 2 to 3 cubic feet per
hour. The torch had a SMITH MW205 braze tip.

[0084] Two steel coupons (low carbon content, SAE 1018 steel) were joined
by brazing. The brazing rod was a Low Fuming Brazing (LFB) rod. The steel
coupons were heated to a cherry red color. The brazing rod was melted to
join the two steel coupons together. That is, the molten blazing rod
material flowed over the two coupons and joined them together by
molecular surface cohesion. The color of the brazing was different than
the color of the steel coupons.

[0086] A gaseous fuel mixture containing 90 volume percent hydrogen and 10
volume percent methane was used in combination with oxygen for welding.
Both gases, the gaseous fuel mixture and compressed oxygen, were
dispensed at a rate of 20 cubic feet per hour to provide a neutral flame.
A standard welding tip (SMITH torch with a standard 205 mixer tip) was
used.

[0087] A 70 S2 wire was used as the welding rod or filling material. 70 S2
wire is commonly used for welding and contains a copper coating around a
carbon steel core. The copper coating acts as a protective barrier
against oxidization from ambient environment such as air and also acts as
an agent that promotes better flow of material, or "puddling". The
melting point and the tensile strength of the welding rod are comparable
to that of the two steel coupons described below.

[0088] Two steel coupons (low carbon content, SAE 1018 steel) were placed
side by side, with one edge of each coupon in contact with the other
coupon. The 70 S2 wire melted slowly but did not flow in a satisfactory
manner because of the relatively low flame temperature. That is, there no
puddles of the molten material formed. The temperature was insufficient
to create a bead of the 70 S2 wire on the surface of the steel coupons.
After welding, the coupons fell apart when the joined part was bent
slightly due to the low weld or joint strength. Stated differently, there
was a lack of fusion of the two coupons together and a lack of
penetration. Further, high levels of sparking suggested that there may be
hydrogen embrittlement.

Comparative Example 2

Welding with Acetylene

[0089] The gaseous fuel mixture of Comparative Example 1 was replaced with
acetylene. The oxygen/acetylene flame was neutral. Two steel coupons were
welded in the same manner as described in Comparative Example 1. The 70
S2 wire melted and flowed sufficiently well to form puddles of the molten
material. A stong weld resulted. When the joined coupons were bent such
that the ends of the coupons opposite the weld touched each other, the
weld did not break.